A study published today in the journal Nature Climate Changesuggests that superstorms and drought aren’t the only affects of climate change already visible. Researchers from America’s National Oceanic and Atmospheric Administration claim that rising humidity is linked to decreased worker capacity in summer months.

According to the study, a global-scale increase in absolute humidity is a fundamental aspect of greenhouse-gas-induced warming. The authors say severe humidity is already reducing people’s productivity by 10 percent during peak months of heat stress around the world, and this is likely to grow to 20 percent by 2050.

When warning of the disastrous effects of climate change, environmentalists often cite rising sea levels, ocean acidification, impact on agriculture, and extreme weather. Although its obvious that these conditions would have an adverse effect on business as usual, few pleas for action ever include an interruption of worker productivity, something that’s likely to materialize long before the worst environmental consequences.

With this study, however, NOAA researchers begin to connect the dots. The researchers combined analysis of humidity and climate change projections with industrial and military guidelines for people’s ability to work under heat stress. In the worst case scenario considered by the model, safe labor would be prohibited in large areas during peak months by 2200, including the entire US east of the Rockies. It’s important to note that they did not include consider labor productivity increases associated with a reduction in adverse conditions of extreme cold, snow and frozen soil.

But, as Professor John Freebairn, an expert in environmental economics at the University of Melbourne’s Department of Economics, points out, the paper does provide “a detailed assessment of just one of the ways in which higher temperatures and humidity across the globe would bring additional costs to society.”

“The impact on productivity shown here, for people not experiencing the increasingly expensive benefits of air conditioning, is going to be quite stark, especially for people in warmer or mid-latitude climates,” agrees David Peetz, professor of employment relations at Griffith University.

Beth Buczynski is a freelancer writer and editor currently living in the Rocky Mountain West. Her articles appear on Care2, Ecosalon and Inhabitat, just to name a few. So far, Beth has lived in or near three major U.S. mountain ranges, and is passionate about protecting the important ecosystems they represent. Follow Beth on Twitter as @ecosphericblog